Put more of your team behind one product.
Share your interface and application logic across platforms. Bring improvements to more users from the same codebase, and spend less time maintaining separate versions.
Explore the Day approach →Day · The universal app framework
One app.
Every platform.
All Day.
Bring your product to desktop, mobile, and web. Day gives your team a shared foundation to build, test, and deliver native apps across the consumer platforms your users call home.
Platform capabilities and release support vary. See current platform support →
More reach. Shared effort.
Build the product.
Bring it everywhere.
macOS, Windows, Linux, iPhone, iPad, Android, HarmonyOS, and the web—all from a single codebase. Keep your product moving forward across devices, with room for the details that make each platform different.
Make every device feel like home.
Give people the controls, text input, menus, and navigation they expect. Day uses each platform’s native interface, so your app belongs wherever it runs.
See Day apps in action →Keep your next market within reach.
Start where your audience is today. Add desktop, mobile, or web as your product grows, building on the work you have already done.
Explore the platforms →The experience your users deserve
Let your app shine
Give your app the performance and polish it deserves. Day pairs platform-native controls with Rust’s bare-metal performance and memory safety, so your shared codebase delivers an experience that feels at home on every device.
Day apps are free from the compromises of other cross-platform toolkits that render to pixels or web views. Your users get familiar text selection, keyboard behavior, scrolling, and accessibility—built on the platform’s own controls.
Explore the native advantage →Compiled for the device
Powered by Rust, Day compiles to machine code on native targets and WebAssembly for the browser.
The platform’s own controls
Text, input, and scrolling draw on the same native toolkits used by the platform’s own applications.
Reactive and declarative
When data changes, Day updates the controls that depend on it. The rest of the interface stays in place.
The complete development lifecycle
From your first idea
to your next release.
Day brings development tools, UI testing, localization, packaging, and release automation into one workflow. Carry the same project from a first prototype through launch and ongoing maintenance.
Create →
Set up a project, choose your platforms, and build your first screens with shared components.
Develop →
Build and run from VS Code. Connect platform services and make the interface your own.
Test →
Replay real app workflows, check results, and capture screenshots across languages and themes.
Release →
Prepare platform packages, configure signing, and manage store listings and release automation.
Improve →
Investigate crashes with user-approved reports and turn fixes into repeatable regression tests.
Use the SDKs, signing credentials, and store accounts required by your release platforms. Day’s tools help coordinate the work.
Day for Visual Studio Code
Your platforms.
One place to work.
Create projects, choose targets, manage devices, and build and launch apps from the editor. Run automated walkthroughs as you work, then open Xcode or Android Studio when you need to go deeper.
Get Day for VS Code
Built to grow with your ambitions
A foundation you can make your own.
Extend what your app can do.
Combine existing controls into reusable components, wrap a native widget, or connect a platform service. Package your additions separately and share them across your products.
Explore the extension framework →Reach more people from the start.
Build for different languages and assistive technologies as part of everyday development. Test translated screens and add accessible labels alongside the interface.
Build for a global audience →Independent. Open source.
Your product’s future belongs to you.
Day is an independent open-source project, built on a shared foundation you can inspect, extend, and contribute to. Choose your own infrastructure and keep the framework’s source within reach.
Available under the Mozilla Public License 2.0.
Explore the source →Read the license →Where will you take your next app?
Start with one idea. Build for a world of devices.